Exhaust fan

ABSTRACT

A COMPACT, LOW-COST, EXHAUST FAN FOR MOUNTING WITHIN A ROOM PARTITIONING WALL OR CEILING COMPRISING, A BLOWER HOUSING HAVING AN OUTLET OFFSET FROM AND PERPENDICULAR TO ITS INLET AND AN AXIAL FLOW TYPE FAN THEREIN, WITH ITS AXIS CENTERED IN THE INLET AND LYING AT AN ACUTE ANGLE THERETO AND ARRANGED TO MOVE AIR THROUGH THE HOUSING BY CENTRIFUGAL FORCE AS WELL AS BY THE PITCH OF THE FAN BLADES.

Sept. 20,1971 RESTHNER 3,606,593

EXHAUST FAN Filed June 30, 1969 States O1 hcc Patented Sept. 20, 1971 ABSTRACT F THE DISCLOSURE a room partitioning wall or ceiling comprising, a blower housing having an outlet offset from and perpendicular to its inlet and an axial flow type fan therein, with its axis centered in the inlet and lying at an acute angle *A compact 10W-Cost exhaust fan for mounting Wlthm l fan 36 suitably mounted on the end of the shaft 38 of thereto and arranged to move air through the housing This invention relates to exhaust fans, and particularly to those adapted to be mounted in partitioning walls or ceilings to withdraw air from the room and exhaust it parallel to and within the wall or ceiling.

-, Heretofore, yin exhaust fans designed for this purpose, the fan has been mounted in a blower housing with its axis parallel to the inlet and perpendicular to the-outlet. When conventional, radial-type vanes were employed in these arrangements, air was moved entirely by centrifugal force, and when yaxial flow type fans were employed in order to reduce cost, the flow generated by the pitch of the blades was substantially reduced by the required abrupt change in direction of air flow.

An object of the present invention is to provide a generally new andimproved exhaust fan which is particularly efficient and inexpensive to produce and sufficiently compact to permit its installation within room partitioning walls of conventional, two-by-four, wood frame construction.

"A further object is to provide an exhaust fan comprising a blower housing having an outlet perpendicular for the purpose in each case. This arrangement does7 how to its inlet and a Vlow-cost, axial flow type fan therein with its bladesV lying at an acute angle to the inlet and outlet. l

A further object is to provide an exhaust fan as set forth in the preceding paragraph in which the blower housing outlet is offset from its inlet and inwhich the axial ow fan is arranged to move air through "theh'ousing by centrifugal force as well as by the pitch of the fan blades.

Further objects and advantages will appear from the following complete description of one form of the invention when read in connection with the accompanying drawing.

In the drawing:

FIG. l'is a front elevational View of an exhaust fan constructed in accordance with the present invention, with the grille and fan blades omitted and with parts broken away for the purpose of clarity; and

FIG. 2 is a cross-sectional View of the exhaust fan taken along line 2 2 of FIG. 1.

Referring to the drawing, a blower housing, generally indicated at 10, is shown attached at one side of the flat side of a vertical, two-byfour, wall framing member 12 by suitable means such as nails 14. The housing 10 is of general rectangular box form having upper and lower horizontal sides 16 and 18, respectively, left and right vertical sides 20 and 22, respectively, and a rear side 24. An outlet 28, offset to the right of the center of the housing with reference to FIG. 1, is formed in the upper side 16 of the housing and includes a short tubular extension 30 adapted to be received in an air duct.

The left side of the housing 10 includes attaching portions 32 extending vertically above and below the housing. These portions 32 each have a locating tab 34 formed at thereto for conveniently positioning and aligning the housing prior to fastening. The depth of the housing is preferably made such that it can be fitted into a conventional partition wall having two-by-four stud framing as well as in a conventional ceiling wherein considerably more space is afforded by the much deeper horizontal joists.

Mounted within the blower housing 10 is an axial flow an' electric motor 40. The fan 36 is formed as a simple, low-cost stamping having a plurality of blades pitched to effect an axial flow of air. The motor 40, which is of simple, two pole, single winding construction, is mounted on a bracket 42. The motor bracket 42 is riveted to the rear and upper sides of the housing by rivets 44. The mounted position of motor 40 is such that its shaft 38 extends inward and upward at an acute angle to the horizontal. The plane of the fan 36 lies, therefore, at an angle intermediate of the perpendicularly related inlet and outlet 26 and 28, respectively, so that axial air flow generated by the pitch of the fan blades is directed inward and upward.

The shaft 38 of the low cost, two pole, single winding motor is centered in the housing 10 with respect to the side walls 20 and 22, see FIG. 1, with the major portion of the motor stator 41 and its single winding 43 offset to the left of the center of the housing and motor shaft while the outlet 2S is offset to the right of the center of the housing 10. This arrangement reduces obstruction to axial flow through the offset outlet 28, generated by the pitch of the fan blades, and provides a relatively unobstructed, tangential outlet for air flow generated by centrifugal force.

It is to be understood that this arrangement is not intended to achieve either the maximum axial flow or the maximum centrifugally generated How of which the fan employed is capable with a housing specifically designed ever, provide a considerably greater composite total flow through a housing having a right angularly related inlet and outlet than can otherwise be achieved in a unit of this compact size employing the illustrated low-cost motor f with a low-cost, stamped, axial flow fan.

The blower housing is further provided with a formed sheet metal fan shroud 46 having a circular opening 48 just slightly larger in diameter than the fan 36. The main portion of shroud 46 lies parallel with the plane of the fan extending downward and inward from the top side 16 of the housing and includes a lower horizontal portion S0 extending to the rear wall 24 of the housing to complete the enclosure. The fan lies within the enclosure formed by the shroud 46, with the outer surface of the fan lying substantially flush with the outer surface of the shroud. The blower housing is further provided with a deflector member 52 extending horizontally along the lower side of the housing and extending inwardly and upwardly from the open side or inlet of the housing to the shroud 46.

The device further includes a protective grille 54 formed as a stamping and overlying the open side or inlet of the blower housing and including a formed peripheral rim portion 56 abutting the finished wall or ceiling surface of a room. The depth of the blower housing is preferably sufficiently greater than the width of a two-by-four wood stud to extend from one side of a stud to lthe finished wall surface at the other side. The grille 54 is provided with a central aperture adapted to receive an attaching screw 58.

The grille 54 is held firmly and resiliently against the finished wall surface by a bracket -60 formed of resilient round wire. The bracket '60 includes a pair of opposed arcuate end portions 62 whirh are threaded through extrusions 64 formed in the vertical side walls of the housing and engage at their free ends the abutments 66 which are formed as extrusions in the shroud 46. The arcuate end portions 62 of bracket 60 are connected by short, transversely extending portions 68 and by a straight portion 70 lying parallel with and spaced slightly inward from the grille. The straight portion 70 is formed with a plurality of close-lying loops 72 midway of its length of suitable diameter, and wound with suitable pitch or lead to provide an internal surface which will receive screw 58 in screw threaded engagement therewith. The straight portion 70 of the bracket is stressed by tightening the screw 58, and the arcuate end portions 62 are stressed between the extrusions 64 and abutments 66 so that the the center line of said opening and the axis of said fan *and to which said fan is attached, and in'which said-motor includes a stator which is offset from the center line of said opening in a direction opposite to` the direction in which said outlet is offset from said inlet.

4. An exhaust fan adapted to be inserted through an opening in thehollow wall of a room and mountedtherein, comprisingl a housing having an inlet in the side thereof facing the room, a motor driven fan in said housing, a grille larger than said inlet and wall opening covering said inlet and wall Opening and adapted to lie against the wall, bracket means resiliently connecting said grille to said housing for rmly and resiliently holding it against l the wall comprising a narrow elongated resilient member bracket 60 as well as the grille 54 is held firmly and resiliently, thereby to preclude any annoying rattling noise which may occur due to vibration when the fan is operating.

It is to be understood that substantial flow increase may be achieved by inclining an axial ow fan to an inlet s the axis of the fan, and the exclusive use of such arrangement is contemplated.

I claim:

1. An exhaust fan adapted to be mounted in the hollow wall of a room adjacent an opening therein and comprising a housing having an inlet formed in one side thereof opening into the room and an outlet formed in a perpendicular side thereof opening into the hollow wall, said outlet being offset laterally from said inlet, an axial How fan with electric driving motor mounted in fixed position in said housing with its axis lying in a plane parallel to said inlet and outlet and substantially on the center of said inlet, and the axis of said fan being inclined to said perpendicular sides of said housing whereby air iiow into and through said housing and through said offset outlet is effected by a combination of fan blade pitch and centrifugal force, and whereby the liow through the housing is diagonal to the inlet and outlet.

2. An exhaust fan as set forth in claim 1 in which said housing is of rectangular box form having an open side forming said inlet, and an opening in a side perpendicular thereto forming said outlet, and an inclined shroud extending across said open side parallel with and framing said axial flow fan.

having relatively short end portions attached to opposite sides of said housing and a relatively long intermediate portion connecting said end portions and bisecting said inlet, said relatively long `connecting portion being spaced inward from said grille and including means intermediate of its length for receiving a screw in screw threaded engagement, and a single screw connecting the central portion of said grille with said resilient member.

A5. An exhaust fan as set forth in claim 4 in which said bracket is formed of round spring wire and in which said means in said long connecting portion thereof for receiving a screw in screw threaded engagement comprises a plurality of closely overlying concentric loops formed therein.

6. An exhaust fan adapted to be mounted in the hollow wall of a room adjacent an opening therein andcompris-v ing a housing having an inlet vformed in one side thereof opening into the room and an outlet formed in a pervpendicular'side thereof opening into the hollow wall,

\ said outlet being offset laterally from said inlet, 'an axial 3. An exhaust fan as set forth in claim 1 in which said electric motor includes a drive shaft lying in the plane of flow fan in said housing with its axis lyiiigsubstantially in a plane through the center of said opening and offset from said outlet, whereby air ilow into and through said housing and through said offset outlet is effected by a combination of fan blade pitch and centrifugal force.

References Cited UNITED STATES PATENTS 4/1936 Fox 98-40 ROBERT M. WALKER, Primary Examiner Us. C1. xn. 98-43; 31u-,172 1 

